[PATCH 1/4] vcs-svn: eliminate global byte_buffer

[Jonathan Nieder <jrnieder@gmail.com>]

Date: Sun, 10 Oct 2010 21:37:10 -0500

The data stored in byte_buffer[] is always either discarded or
written to stdout immediately.  No need for it to persist between
function calls.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
For the line_buffer library.  Decreases BSS size.  Increase stack
overhead of two I/O functions by 4096 bytes.  Performance effect
hasn't been measured.  Alas there is no stdio wrapper for sendfile; if
there were, we could eliminate the buffer altogether.

Of course the goal is to make line_buffer more easily reusable, by
eliminating _all_ global state.  I assume David would like this but I
don't remember if he said so.

 vcs-svn/line_buffer.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/vcs-svn/line_buffer.c b/vcs-svn/line_buffer.c
index 1543567..f22c94f 100644
--- a/vcs-svn/line_buffer.c
+++ b/vcs-svn/line_buffer.c
@@ -14,7 +14,6 @@
 obj_pool_gen(blob, char, 4096)
 
 static char line_buffer[LINE_BUFFER_LEN];
-static char byte_buffer[COPY_BUFFER_LEN];
 static FILE *infile;
 
 int buffer_init(const char *filename)
@@ -68,6 +67,7 @@ char *buffer_read_string(uint32_t len)
 
 void buffer_copy_bytes(uint32_t len)
 {
+	char byte_buffer[COPY_BUFFER_LEN];
 	uint32_t in;
 	while (len > 0 && !feof(infile) && !ferror(infile)) {
 		in = len < COPY_BUFFER_LEN ? len : COPY_BUFFER_LEN;
@@ -83,6 +83,7 @@ void buffer_copy_bytes(uint32_t len)
 
 void buffer_skip_bytes(uint32_t len)
 {
+	char byte_buffer[COPY_BUFFER_LEN];
 	uint32_t in;
 	while (len > 0 && !feof(infile) && !ferror(infile)) {
 		in = len < COPY_BUFFER_LEN ? len : COPY_BUFFER_LEN;
-- 
1.7.2.3.554.gc9b5c.dirty